Original Owner Of Monitor 5JR Plus

melchionda

The plot thickens. Having just finished another upgrade project I couldn't help but tear into these Polks. I guess I'm not crazy but I am a little confused. I guess these really are Polk Monitor 5Jr+ speakers even though the name plate on the back says "Polk Monitor 5" (See my earlier post with a photo of that). Both the woofer as well as the tweeter are stamped "M5 JR +" Can someone tell me what speakers these are? Also, about the tweeter. Is the SL2000 the desireable tweeter?

melchionda

I'm thinking that since the inductors are both air core inductors I'll keep those and just get a new capacitor and resistor and build out a new crossover on a piece of MDF. I'll also plug the current circular hole and put in some higher quality binding posts. I have an extra set of GR Research Tube Connectors that I was thinking I would use for this. What is the little blue thing? Is that the "protection switch"/fuse that I've heard some people mention?

xschop

Jumper the blue polyswitch when you add new caps and resistors.
Those 5Jr+ crossovers are the same as 5Jr (non-passive radiator)

The SL2000s can either be modded for wuhan silks $20, or you can RDO them for and extra $120

Gardenstater

SL2000 isn't spoken of highly on the forum and DarqueKnight's testing showed that (Tale of 5 Tweeters). RD0194 is the direct swap upgrade. RD0198 is the best but you have to slightly modify your crossover to use (and one of the connection fastons), as I said previously. You would probably have to use a couple of ClarityCap CSA 6.8uF (or other) in parallel to get close to the 13.5uF Polk used in the 5jr+ Series II. That is assuming they didn't change the wire awg, and thus the DC resistance of the inductors.

pitdogg2

Why on earth would you cut the wires from the binding post and inductor to the crossover ?

melchionda

pitdogg2 wrote: »

Why on earth would you cut the wires from the binding post and inductor to the crossover ?

Because I’m completely rebuilding the crossover with new parts.

melchionda

Here is a Pro tip on removing vinyl veneer from this speaker... Using a clothing iron and a layer of aluminum foil makes fast work of this job. I just put the iron on the hottest setting and put the piece of aluminum foil between the iron and the speaker. I then let the iron sit for about a minute, occasionally checking the vinyl. When it started to bubble I started pulling on the end of the vinyl. Its much easier if you don't tear the vinyl. Leave the peeled part nice and big so you can grab it. Also, only use a scraper to start the vinyl.... once you have pulled up a little piece start pulling on it with your fingers. It comes up really easy. I'm spending more time letting the iron warm up the vinyl than I am actually removing it.

melchionda

In the last 30 minutes I just did three sides of this speaker. And no glue residue left behind either.

F1nut

A heat gun is my choice.

melchionda

There are lots of options for crossover components I just pulled the trigger on these and was hoping you guys could tell me if I went wrong anywhere...

Note that I am also upgrading my tweeter to the RD0198-1.

Resistors
https://www.parts-express.com/Mills-1-Ohm-12W-Non-Inductive-Resistor-005-1

Capacitors
https://www.parts-express.com/Jantzen-0570-6.8uF-800V-Z-Superior-Capacitor-027-494

Coils
https://meniscusaudio.com/product/0-56mh-18-ga/

https://meniscusaudio.com/product/0-20mh-20ga/ (Modified to .19mh and 22awg wire)

Gardenstater

I don't know about going "wrong" but another option was these, on sale 20% off. They would have been about 1-1/4" less in length if space is an issue:

https://www.partsconnexion.com/AURIXO-75923.html

melchionda

Double post….sorry

melchionda

I see that my other thread about my 5JR+ veneer question has turned into more than just that.... I figured I would try to bring things back to this thread. So here are my progress pics so far.

Vinyl veneer removed

melchionda

Internal bracing via a 1" dowel as well as a patch over the crossover hole in the back wall.

melchionda

Filling in and sanding the back of the cabinets.

melchionda

I removed the small "step" around the outside of the front baffle with my router and then filled in the groove with bondo.

melchionda

I plan to remove the bevel around the front baffle and then create a round over out of solid walnut. In removing material from the top of the cabinet I exposed a void in the front baffle. Its interesting that Polk built these speakers with a void around the front baffle. Any one have any ideas as to what this may have been for? I plan to fill it in.

melchionda

Next... routing the front edges of the baffle and more bondo work.

melchionda

I routed the front corners of the cabinets. I will fill these empty corners with a strip of Walnut so that I can route the front corners into a roundover.




I shaved 1/2" off the top surface of the cabinets. I plan to replace the 1/2" of particle board that I removed with a 1/2" solid walnut.




Much like the top of the speaker cabinet, routing the front edges of the cabinet exposed a void. I filled the void with Titebond II. I also added a coat of flat black paint to the driver driver cut-outs.




Next step is to touch up some of the minor routing mistakes and then being adding the walnut corners, veneer and panel surfaces.

xschop

Great thread and great attention to detail.

melchionda

Here is what I plan to do with those corners. (The square walnut moldings will be routed down so that they are flush 1/4 round with roughly a 1/2" radius.)



I had to add Bondo to the corner voids because the glue was shrinking too much.


Starting to add Veneer

melchionda

The veneer went on easy, however I just ran into my first problem....

How do you route around the speaker driver holes with precision? I got a BOSCH 85285 1/4 In. x 1/4 In. Carbide 1-Flute Flush Trim Bit but the recesses on this baffle are not deep enough for it. I tried to grind off a bit of the tip of it but its tungsten carbide so its too hard to remove material from it.

txcoastal1

Yikes,
Template
Press the baffle veneer between 2 pieces of 3/16 or thinner plywood
Going to be like applying vinyl decals

Gardenstater

I think a rabbeting bit would work but I worry about chipping. The bearing on the bit will follow the thru hole, not the rabbet. You could try clamping some 1/4" Luan (maybe MDF would be better) or the like to the front baffle, that has holes cut out that are undersized relative to the speaker holes. That might prevent chipping of the veneer.

melchionda

To cut the veneer around the driver openings I ended up getting one of these...

https://www.holbren.com/Whiteside_Machine_SC28C?gclid=CjwKCAjwov6hBhBsEiwAvrvN6Nqz7DwaU1ED4xoW7Uh3iM1UM2LH5a7Rte7O7a-mH1l6vsG7WjrY4hoCpO0QAvD_BwE

I don't anticipate a problem with the mid/base driver and passive radiator openings, hopefully the guide will be short enough to cut the veneer around the tweeter recess.

Meanwhile, I'm gluing the walnut panels onto the back, top and bottom of the speaker cabinets.

xschop

I've got the tweeter bezel corners at 0.375" radius.
If you can set up on a press with a 3/8" end mill, you could cut them that way...JAT

melchionda

xschop wrote: »

I've got the tweeter bezel corners at 0.375" radius.
If you can set up on a press with a 3/8" end mill, you could cut them that way...JAT

Unfortunately I do not have any tools like that. I have a router, chop saw and some dewalt hand tools and thats about it.

I was having some work done on my house so for the past few weeks I've had access to the tools my contractor had on site, but he finished the project and started to pull everything off of the site yesterday.

joebass3

Excited to see these when they are done! Since you put veneer on the sides first before gluing the other solid pieces on, will the end grain be visible at the top and bottom?

Gardenstater

That dado laminate trimmer tool has a minimum depth of "dado" requirement of 1/8" but if you have a bench grinder you could grind the end of it down but you will need the right wheel that can grind carbide. Offhand I do not know what would be best and most affordable. I know diamond would work. Edit - Green Silicon Carbide is good too.

A dremel tool or right angle grinder would work as well.

xschop

How about a 3/8" leather punch to scribe, then use and exacto knife?